This system and method involves document printing with ink jet equipment with respect to high speed document processing.
One of the major problems involved in document processing relates to high-speed printing on documents which pass by ink jet printing devices at very high-speeds. For example, this occurs in the transport of paper documents at speeds of 150 inches per second, such as functions in the Unisys Corporation""s Unisys NDP 1150 document processing machine and other similar systems. A single cartridge acting alone could be made able to print an endorsement statement, or marking on each document as it passes by the print head. However, these printouts generally will have a most unacceptable degree of contrast. As a result, such single cartridge printing systems very often provide poor markings or endorsement on documents which pass by at these very high speeds. It has long been hoped that some system and method could be developed to provide a more reliable definite and higher contrast implementation on each document as it passes at the very high speeds, but heretofore this problem has never been cleanly addressed.
Accordingly, it is an object of the present invention to address the problem of poorly printed out contrast characters and numbers having minimal contrast which constitute endorsements on various documents, such as checks which pass at high speed past the printing head.
The present system and method provides for a dual cartridge ink jet system which allows a much higher and more readable contrast level and is able to achieve a near-letter quality printing level even though the documents pass at very high speeds past the print head.
The present system and method involves a user-friendly document-endorsing system using dual ink jet cartridges for high speed printing, often at paper speeds of up to 150 inches per second. In order to overcome the problem of poor print-out quality at these high speeds of document motion and transfer, each one of the two dual cartridges is arranged to print an identical pattern on the same target area of a document as it passes each respective print head.
Two adjacent and like ink jet cartridges are mounted in a Unisys NDP 1150 check processing/endorsing is machine. The two cartridges are separated by a distance xe2x80x9cSxe2x80x9dwhich in this case, is set at 1.5 inches. The document being printed upon is presented for movement by guiding the document between two flat drive belts which advance the document, such as a check, for example, at a rate of 150 inches per second past the print head surface of each of the cartridges. A document guide spaces a document at approximately 0.050 inches, (less the document thickness), from the print head""s array plate. This spacing will be made to vary during the printing process, depending upon the document condition and thickness.
As the document or check moves past the multiple ink spray jet heads, the firing of the jets is phased and synchronized so that after the first jet has placed its marking on the document, then after a subsequent delay, the second jet spray head will place the exact same marking on the exact same spot or target of the document.
In order to overcome any mechanical tolerances or misaligned target points, the firing synchronization and direction is adjustable by service personnel to adjust the timing between the respective cartridge firings until the print patterns produced by the two cartridges are effectively co-incident and overlie each other precisely on the same target area during a test run on a test document. Software is often used to vary the timing between the respective cartridge firings. However, other electronic means may also be utilized to set this delay between the firing of the two ink jet cartridges.